I think it is worth speaking to nursery, good to get their input at this point in case you do need to look into it later (and most services seem to have 6 years as a starting point; unless there are very very obvious problems later on).
For context though - I am neurodivergent myself and wasn’t diagnosed with ADHD/ASD until I was an adult.
One of my DD’s is autistic. However, she never had any obvious stims until she was around 8, and she never engaged in echolia. She is academically able and “ masks” well in a school most of the time but has meltdowns and anxiety before and after school.
My other DD did (and still does at times) the repetitive throat clearing. She is not autistic or ADHD and has no particular issues - but she does have mild dyspraxia. For her, the throat clearing seemed to be associated with stressful times and anxiety.
Eldest DS did have echolia from television when young, and was an unusually early talker with an advanced vocabulary. He is definitely not autistic (a young adult now) but I feel confident he has ADHD, we just missed it when he was young as I didn’t know much about it then.
What I’m trying to say (in a very long winded way 😂) is that it could be something or nothing but it worth keeping an eye on. Do you think you or your husband could be neurodivergent but not diagnosed? As it often seems to run in families.
I wish I’d got my DD on the ASD pathway at 6 - as I started to suspect something was going on then - but actually waited until she was 8. There is a long wait on the NHS so I wished I’d got the ball rolling earlier.
We did see a private occupational therapist though, for a sensory integration assessment, and that was very helpful.
Also, when I had the developmental history apt for DD, I found it very hard to remember those early years and hadn’t kept nursery reports etc, so you are doing the right thing to be aware now.
If your DD does go on to need any extra support in school ( and she might not, she might just be a bit of an introvert who needs recovery time after being around people or have sensory issues) then it should be provided based on her needs rather than diagnosis , you don’t have to wait.